The technology of computed tomography units is generally known. Reference may be made in this context to two papers entitled “Bildgebende Systeme für medizinische Diagnostik” [“Imaging systems for medical diagnostics”], ISBN 3-89578-002-0, in particular Chapters 5 and 9, and to “Computertomographie” [“Computed tomography”], ISBN 3-89578-082-0, in particular Chapter 3, preferably to Chapter 3.4.
Cardiac computed tomography units that are suitable for the three-dimensional display of the periodic heart movement are likewise described in patent literature. Reference may be made by way of example to the applicant's laid-open patent applications DE 199 57 082 A1, DE 199 57 083 A1, DE 198 42 238 A1, DE 198 42 240 A1, DE 197 40 214 A1 and DE 196 22 075 A1.
The use of such cardiac CT units renders it possible to represent the movement of the heart by making three-dimensional recordings of the heart over the entire course of the movement. That is to say, it is therefore possible to produce an image sequence that displays the movement of the heart three-dimensionally in the manner of a film by juxtaposing a multiplicity of temporally offset 3D image sets.
When viewing such a series diagnostically, the problem arises that the images recorded by the computed tomograph are basically at first available in views which correspond to the patient's longitudinal axis, since this corresponds to the normal infeed direction of the patient couch when making CT recordings. However, it is advantageous for the diagnostic assessment to view a display of the heart in specific preferred directions such as, for example, the “long heart axis”, the “short heart axis” or a recording axis that corresponds to the so called “4-chamber view or 5-chamber view”.
With the units currently on the market, these recording sequences are produced in the desired viewing mode by respectively producing the individual 3-dimensional recordings of the desired image sequence individually from the primary data of the CT and reproducing them on a monitor, the operator subsequently having to input the desired image parameters such as slice thickness, axis orientation etc. These inputs are used to calculate and store the desired view from the available 3D display in z-direction.
During the conversion process of the image sequence into the desired view, this procedure repeatedly requires the desired recording parameters to be input manually. Thus, in this case the process of reconstructing a 3D recording set of a specific cardiac phase by inputting the desired image parameters, converting the view in accordance with the desired image parameters and subsequently storing this changed 3D recording set is repeated until all the individual phases of the heart have been represented such that an entire image sequence composed of a multiplicity of 3D recording sets with the desired image parameters is subsequently present.
Such a method is complicated and affected by error. Furthermore, this entails a high arithmetic capability that is not mandatory.